There is a need to prevent and control weeds in crop planting process. If a crop is capable of obtaining resistance capability to broad-spectrum herbicides, the weeds of such crop can be prevented and controlled by spraying broad-spectrum herbicides after the seedling emergence. Such prevention and control method for weeds is simple, highly efficient, low in cost, and safe to crops.
Crops can acquire resistance to a herbicide through genetic engineering improvement. For example, crops can obtain glyphosate resistance capability through transgenic expression of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) of Agrobacterium (Agrobacterium tumefaciens sp CP4). Transgenic glyphosate-resistant plants expressing such enzymes have been applied in production (U.S. Pat. Nos. 453,590, 4,769,061, 5,094,945). In order to control the occurrence of herbicide resistance of weeds, to improve the resistance level of the transgenic crops and to increase the diversity of the resistance genes, it is very useful to develop resistant transgenic crops in production which are resistant to other herbicides than glyphosate.
Cytochrome P450 is a large gene family. Usually, there are more than 200 P450 genes in a plant. It is found in prior study that part of the P450 genes are genes capable of degrading herbicides. For instance, a hybridized molecule of a cytochrome P450 gene P4507A1 of an animal and a NADPH-cytochrome P450 gene of a yeast can be resistant to a herbicide. (Shiota et al. 1994 Plant Physiol. 106: 17). CYP71A10 is a cytochrome P450 gene isolated from soybean, and the resistance of transgenic tobacco to Linuron and chlortoluron can be improved by expressing such gene in tobacco. (Siminszky et al., 1999 Proc Natl Acad Sci USA 96: 1750-1755; Siminszky et al, 2000, Weed Sci 48:291-295). A cytochrome P450 gene (having a polynucleotide sequence of SEQ ID: 5 and an amino acid sequence of SEQ ID: 6) in maize is found to have the capability of resistance to herbicides such as nicosulfuron (Chinese patent, application number 200610155661; and US patent US 20080052798 A1). A cytochrome P450 gene in rice also has resistance to Bentazon and sulfonylurea herbicides (Pan et al., Plant Molecular Biology, 2006, 61: 933-943). Other cytochrome P450 genes from different sources also have the function of resisting herbicides and can be used to obtain transgenic plants resistant to herbicide. For instance, Didierjean et al. (2002) Plant Physiol. 130: 179-189; Morant et al. (2003) Opinion in Biotechnology 14:151-162.
The present invention provides genes resistant to several highly efficient herbicides and a method for obtaining transgenic herbicide-resistant plants using the genes.